Does someone know why some recipes (like jams or marmalades) require restof the mass in their recipe

Joined Jan 6, 2018

as the title of the thread says, some jam or marmalade recipes require that the preparation rests until chilled after being cooked at around 70-80C for two hours, and this process is repeated even for 3 or 4 times. Does someone know the theoretical or practical background of this process?

My main worries are the food safety rules within those resting periods (which normally are outside the refrigerator).

If someone could point me in the right direction, would be deeply appreciated!

Thank you!
Joined Sep 27, 2014
Now that's interesting. What recipe are you referring to? Your jam or marmalade need heat and time to activate the natural pectin in the fruit or the added pectin and reduce the liquid, but I fail to see why you would need to cool it down and heat it again.



Joined Jan 6, 2018
The food safety part you really don't need to worry too much. Marmalade and jam have a very high sugar content and very low water content. I'd imagine it has something to do with the water content. you want to cook out the water without burning the sugar, Not sure tho:)
Joined Jun 27, 2012
Would you mind citing your recipe and source?
Would go a long way in helping you decipher this mystery.

Joined Jan 8, 2010
Maybe to check the tickness?
Jam/marmelade thickens when it cools down.
Can't think of another reason
Joined Jan 4, 2018
It's probably one of those nonsensical ritualistic practices that grandmothers did long before food science was invented. I have often watched my mother and grandmother do those things in total bewilderment, but I've never had the heart to correct them.
Joined May 5, 2010
I believe I can help. I've been making jams, jellies, and Apple Butter now going on 20 years. It all has to do with Pectin...either natural or the powdered stuff you add. Resting the jam before chilling is a part of the setting process. Someone also mentioned evaporation, and yes a certain amount of reduction takes place before the setting can begin.
Joined Jun 27, 2012
My SOP is always cook until it is reduced a certain amount and then do a gel test and if it passes then jar and finish the process.
Many low pH/high sugar content recipes don't even need to be processed (fill jar and cap then place on a clean towel and the jar will seal nicely) but if I am using a new recipe I will always follow the written directions exactly the first time.

...but as to the cook and and cool and repeat several times just because the recipe directs?

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